You are looking at the HTML representation of the XML format.
HTML is good for debugging, but is unsuitable for application use.
Specify the format parameter to change the output format.
To see the non HTML representation of the XML format, set format=xml.
See the complete documentation, or API help for more information. 
<?xml version="1.0"?>
<api>
  <query-continue>
    <allfileusages gafcontinue="GravitySuitIcon.png|162" />
  </query-continue>
  <query>
    <pages>
      <page pageid="2" ns="0" title="TXTR (Metroid Prime)" />
      <page pageid="8" ns="0" title="AGSC (File Format)" />
      <page pageid="26" ns="0" title="CMDL (Tropical Freeze)" />
      <page pageid="32" ns="0" title="DSP (File Format)" />
      <page pageid="42" ns="10" title="Template:Todo" />
      <page pageid="54" ns="0" title="STRG (Metroid Prime)" />
      <page pageid="56" ns="3" title="User talk:Embyr 75/Sandbox" />
      <page pageid="57" ns="0" title="CSMP (File Format)" />
      <page pageid="122" ns="0" title="CINF (File Format)" />
    </pages>
  </query>
</api>